No oranges compare to Greek oranges.
Not Florida, Texas, or Arizona. Honorable mention must be given to Spain, Italy, and Portugal (whence the Greek [and Bulgarian, Turkish, and Romanian] name for orange—Portokalli) derives. Greek oranges, however, are simply the best.
I would also suggest, based on my own research living in Greece, that the oranges of the Argolid Plain top the Greek list, followed closely by the Laconian version. I used to buy 5-kilo sacks of them off of roadsides outside of Athens, but of course, the best was when you tied it with a trip to the Argolid, one of our favorite road trips when we lived in Greece.
To be truthful, our road trips often resulted in several pit stops along the way. I often invited myself into Nemean wineries for a tipple and a few bottles at exhibition prices not available in Athenian supermarkets. Further, though the quality varied considerably, I would often stop by roadside stalls for local wines, sulfite-free, which could vary from next-to-vinegar to out-of-this-world. As in Attican Kaves, which I haunted for retsina, my slight American accent intrigued them, as they had an impression that a Greek-American would not buy in such places.
But I digress from oranges. For months at a time, 5-kilo bags of oranges, often a few hundred meters from their trees, were to be had for a song. On most return trips from the Argolid, the car would be at least 15 kilos heavier. Something about the trees there, in the reddish soil which has yielded riches to over four millennia of continuous civilization, in the shadows of Mycenaean metropolises, classical ruins, Byzantine and Venetian forts, that destines these fruits to be far deeper and sweeter experience than those of a Florida plantation.
Back at our Athenian home, we invested in a juicer with a good motor, and the economics made sense, as an orange juice from the nearby café at the Palia Plateia tis Filotheis (Old Filothei Square) would run you six euros a pop.
Whenever the oranges were in season, before setting out from our northern suburb home to my banking job in Kallithea (which means a good view, but I never saw such a view from there), I would fortify myself with an orange juice freshly squeezed to brave the onslaught of Athenian traffic. A good start to a rough day.
I have had Greek oranges outside of Greece when we lived in Serbia, but unfortunately, these fruits do not make the Transatlantic flight, and like certain pleasures, they must be enjoyed in situ.
Next year, in Greece. But if you are in Greece, drink as much orange juice as you can.